The present invention concerns a forming method for forming part of or the entire circumference of a cylindrical work piece into circular or deformed circular shape, such as ellipse, etc., for example, by executing forming on a cylindrical work piece, and an apparatus for such forming.
Forming work on cylindrical work piece includes drawing, cutting, etc., for example.
Usually, when executing such forming work, or in the case where a cylindrical work piece is formed into circular shape by means of a processing tool mounted on a spindle, for example, the processing is preformed by fixing the work piece and turning the spindle together with the processing tool, while moving the processing tool mounted on a spindle in the radial direction of the spindle.
In that case, however, the mechanism for moving the processing tool mounted on a spindle in the radial direction of the spindle becomes extremely complicated in structure, presenting problems of high manufacturing cost and difficulty of maintenance.
Moreover, from a structural reason of said mechanism, it is very difficult to form, by drawing, in a deformed circular shape such as an ellipse, etc. Because of this difficulty, processing of the muffler of an automobile, etc. used to be made by a method which consists in forming pieces in half size by punching, etc., putting them together and forming them into an integrated body by welding, etc. But this method also had problems of troublesome manufacturing processes, and high manufacturing cost due to complication of manufacturing processes such as manufacture of forming dies to be used for punching and setup process, etc.
The objective of the present invention is to provide a forming method for forming part of or the entire circumference of a cylindrical work piece into a circular or deformed circular shape, such as an ellipse, etc., for example, by executing forming work on a cylindrical work piece, and an apparatus for such method that is capable of solving said problems of conventional forming method for cylindrical work piece.
The forming method for a cylindrical work piece according to this first invention, for achieving said objective, is a forming method for executing forming work on a cylindrical work piece, by means of a forming apparatus comprising a spindle mechanism provided with a processing tool mounted at the tip of the spindle, and a holding mechanism for holding a cylindrical work piece disposed in such a way that it faces the spindle mechanism, characterized in that prescribed forming work is executed on the work piece, by putting the holding mechanism in a prescribed shifting motion, while shifting the spindle mechanism and the holding mechanism relatively in the axial direction of the spindle, and by relatively shifting said processing tool along the outer circumference of the work piece.
This forming method for a cylindrical work piece, realized in such a way that prescribed forming work is executed on the work piece by putting the holding mechanism in a prescribed shifting motion while shifting the spindle mechanism and the holding mechanism relatively in the axial direction of the spindle, and by relatively shifting the processing tool along the outer circumference of the work piece, can secure a high degree of freedom for the relative shifting of the processing tool against the work piece, and can execute forming work on a cylindrical work piece into circular or deformed circular shapes, such as an ellipse, etc. for example, easily and with high accuracy.
Moreover, in addition to the above, it can also simplify the structure on the spindle side, which is liable to be a complicated structure, reduce the manufacturing cost of the apparatus, and facilitating maintenance thereof.
In this case, the shifting motion of the holding mechanism may be a circular motion.
This makes it possible to keep the worked section of the work piece in a circular shape.
Furthermore, the shifting motion of the holding mechanism may be a deformed circular motion such as ellipse, etc.
This makes it possible to keep the worked section of the work piece in a deformed circular shape such as ellipse, etc.
Still more, the center of the shifting motion of the holding mechanism may be deviated from the center axis of the spindle.
This makes it possible to execute processing work by keeping the center axis of the processed part of the work piece deviated from the center axis before processing of the work piece.
Yet more, the center of shifting motion of the holding mechanism may be deviated at a prescribed inclination against the center axis of the spindle.
This makes it possible to execute processing work by keeping the center axis of the processed part of the work piece inclined against the center axis before the processing of the work piece.
Moreover, the forming method may be realized in such a way as to make the inclination changeable during forming.
This makes it possible to execute processing work in a curved shape in which the center axis of the processed part of the work piece is inclined against the center axis before the processing of the work piece.
Furthermore, a drawing tool or a cutting tool may be used selectively as processing tools, to enable the selective execution of drawing or cutting on the work piece.
This makes it possible to selectively execute drawing and cutting on the work piece, simplify the manufacturing processes and improve production efficiency.
Moreover, the forming apparatus for a cylindrical work piece according to this second invention, which is an apparatus for implementing the forming method for a cylindrical work piece of this first invention, is a forming apparatus for cylindrical work pieces comprising a spindle mechanism provided with a processing tool mounted at the tip of the spindle, and a holding mechanism for holding the cylindrical work piece disposed in such a way as to face the spindle mechanism, it is provided with an axial shifting mechanism for relatively shifting the spindle mechanism and the holding mechanism in the axial direction of the spindle, a shifting motion mechanism for enabling the holding mechanism to make a prescribed shifting motion, and a control mechanism for driving the axial shifting and shifting motion mechanism in linkage with each other.
This forming apparatus for a cylindrical work piece, realized by comprising an axial shifting function for shifting the spindle mechanism and the holding mechanism relatively in the axial direction of the spindle, a shifting motion function for enabling the holding mechanism to make prescribed shifting motions, and a control mechanism for driving said axial shifting and shifting motion functions in linkage with each other, can simplify the structure on the spindle side, which is liable to be a complicated structure, reduce the manufacturing cost of the apparatus, and facilitate maintenance thereof.
Furthermore, in addition to the above, it can secure a high degree of freedom for the relative shifting of the processing tool against the work piece, and can execute forming work on a cylindrical work piece into circular or deformed circular shapes, such as an ellipse, etc. for example, easily and with high accuracy.
In this case, the shifting motion function may be comprised of two linear shifting means for shifting the holding mechanism in a prescribed direction and in the direction orthogonal to it, to enable the holding mechanism to make prescribed shifting motions by driving the two axial shifting mechanism in linkage with each other with the control mechanism.
This makes it possible to construct the shifting motion function with the two linear shifting functions and to simplify the structure of the shifting motion function, to further reduce the manufacturing cost of the apparatus and facilitate maintenance thereof.
Still more, a holding mechanism deviating function may be provided for deviating the axis of the holding mechanism at a prescribed inclination against the center axis of the spindle.
This makes it possible to execute processing work by keeping the center axis of the processed part of the work piece inclined against the center axis before processing of the work piece.
Yet more, a drawing tool or a cutting tool may be used selectively as processing tools.
This makes it possible to selectively execute drawing and cutting on the work piece, simplifying the manufacturing processes and improving production efficiency.